Active-threshold-control type self-cooling engine

ABSTRACT

The present invention provides an active-threshold control system for the self-cooling engine to improve the energy efficiency of the self-cooling-16-process. 
     The active-threshold-control type self-cooling engine consists of a primary-power-cylinder and a secondary-power cylinder and a cooling-cylinder and an active-threshold-control system that controls the initiation timing of each injection-process with the active-cooling-phase, thereby limiting the maximum compression pressure in each coordinate-channel and reducing the energy loss during the first-cold-compression-process and the second-cold-compression-process.

FIELD OF THE INVENTION

The present invention is a continuing application of the dual six-stroke self-cooling internal combustion engine; and more particularly the present invention relates to an advanced coordination control method for the self-cooling internal combustion engine that operating with the self-cooling-16-process.

BACKGROUND OF THE INVENTION

The present invention is a continuing application of the dual six-stroke self-cooing internal combustion engine, which was previously filed as U.S. Pat. No. 7,143,725, and the engine of this type can also be abbreviated as the self-cooling engine.

SUMMARY OF THE INVENTION

It is the main objective of the present invention to provide an active-threshold-control type self-cooling engine that can adjust the initiation timings of the first-injection-process and the second-injection-process with the active-cooling-phase, thereby limiting the maximum compression pressure of the cooling-cylinder during the first-cold-compression-process and the second-cold-compression-process in the heavy load condition.

It is the secondary objective of the present invention to provide an active-threshold-control type self-cooling engine that can improve the overall energy efficiency for a wide range of engine rpm and engine load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows the valve condition of the first embodiment at the beginning of the primary-intake-process at approximately 15 degree of crankshaft reference angle.

FIG. 1B shows the valve condition of the first embodiment at the beginning of the first-recharge-process at approximately 105 degree of crankshaft reference angle.

FIG. 1C shows the valve condition of the first embodiment at the beginning of the primary-compression-process at approximately 195 degree of crankshaft reference angle.

FIG. 1C shows the valve condition of the first embodiment at the beginning of the first-cold-compression-process at approximately 260 degree of crankshaft reference angle.

FIG. 1E shows the valve condition of the first embodiment at the beginning of the primary-hot-expansion-process at approximately 365 degree of crankshaft reference angle.

FIG. 1F shows the valve condition of the first embodiment at the beginning of the first-injection-process at approximately 410 degree of crankshaft reference angle.

FIG. 1G shows the valve condition of the first embodiment at the beginning of the primary-cold-expansion-process at approximately 435 degree of crankshaft reference angle.

FIG. 1H shows the valve condition of the first embodiment at the beginning of the primary-exhaust-process at approximately 550 degree of crankshaft reference angle.

FIG. 1I shows the valve condition of the first embodiment at the beginning of the secondary-intake-process at approximately 370 degree of crankshaft reference angle.

FIG. 1J shows the valve condition of the first embodiment at the beginning of the second-recharge-process at approximately 465 degree of crankshaft reference angle.

FIG. 1K shows the valve condition of the first embodiment at the beginning of the secondary-compression-process at approximately 555 degree of crankshaft reference angle.

FIG. 1L shows the valve condition of the first embodiment at the beginning of the second-cold-compression-process at approximately 620 degree of crankshaft reference angle.

FIG. 1M shows the valve condition of the first embodiment at the beginning of the secondary-hot-expansion-process at approximately 725 degree of crankshaft reference angle.

FIG. 1N shows the valve condition of the first embodiment at the beginning of the second-injection-compression-process at approximately 770 degree of crankshaft reference angle.

FIG. 1O shows the valve condition of the first embodiment at the beginning of the secondary-cold-expansion-process at approximately 795 degree of crankshaft reference angle.

FIG. 1P shows the valve condition of the first embodiment at the beginning of the secondary-exhaust-compression-process at approximately 915 degree of crankshaft reference angle.

Sequence Table.1L shows the operation of the active-threshold-control system when the active-cooling-phase is set to 45 degree for advancing the threshold angles in the extremely light load condition.

Sequence Table.1M shows the operation of the active-threshold-control system when the active-cooling-phase is set to 75 degree for adjusting the threshold angles in the medium load or light load condition.

Sequence Table.1H shows the operation of the active-threshold-control system when the active-cooling-phase is set to 120 degree for delaying the threshold angles in the heavy load condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The active-threshold-control type self-cooling engine is an improved internal combustion engine developed from the dual six-stroke self-cooling internal combustion engine; however, the 12-stroke-sequence and the self-cooling-16-process of the self-cooling engine will be defined in a more detailed and clear fashion with the specific terms and the structure elements in the present invention.

The structure of the active-threshold-control type self-cooling engine comprises a primary-power-cylinder and a secondary-power-cylinder and a cooling-cylinder and an active-threshold-control control system; said three cylinders will co-act in the 12-stroke sequence and the self-cooling-16-process, and each process duration of the self-cooling-16-process will be shifted according to the changes in the initiation timings of the first-injection-process and the second-injection-process resulted from the different settings of the active-cooling-phase.

In the drawings of FIG. 1A to FIG. 1P, the components are labeled with the following reference number, the primary-power-cylinder 10, the secondary-power-cylinder 20, the cooling-cylinder 30, the primary-piston 11, the secondary-piston 21, the cooling-piston 31, the main-crankshaft 190, the synchronization-gear 198 of the main-crankshaft, the sub-crankshaft 180, the phase-gear 188, the primary-intake-valve 12, the secondary-intake-valve 22, the cooling-intake-valve 32, the common-intake-manifold 101 (shared by primary-power-cylinder and the secondary-power-cylinder), the cooling-intake-manifold 102, the primary-exhaust-valve 18, the secondary-exhaust-valve 28, the primary-coordinate-channel 60, the secondary-coordinate-channel 80, the first-input-valve 61, the second-input-valve 81, the primary-coordinate-valve 65, the secondary-coordinate-valve 85, the ignition means 15 of the primary-power-cylinder, the ignition means 25 of the secondary-power-cylinder.

The primary-power-cylinder 10 contains a reciprocating primary-piston 11, the secondary-power-cylinder 20 contains a reciprocating secondary-piston 21; the cooling-cylinder 30 contains a reciprocating cooling-piston 31.

The primary-piston 11 and the secondary-piston 21 are connected to a main-crankshaft 190, while the cooling-piston 31 is connected to a sub-crankshaft 180; the main-crankshaft 190 will output power to the output section 199.

The sub-crankshaft 180 will be synchronized and driven with the main-crankshaft 190 with chains or gears, and the sub-crankshaft 180 can change its relative rotation-phase with the main-crankshaft 180 with a phase-gear 188, thereby adjusting the active-cooling-phase among said three cylinders.

The primary-power-cylinder 10 includes air-intake means (12) and exhaust-means (18) and fuel-supplying means and ignition means (15).

The secondary-power-cylinder 20 includes air-intake means (22) and exhaust-means (28) and fuel-supplying means and ignition means (25).

The cooling-cylinder includes air-intake means (32).

The active-threshold-control system includes a primary-coordinate-channel 60, a primary-coordinate-valve 65, a first-input-valve 61, a secondary-coordinate-channel 80, a secondary-coordinate-valve 85, a second-input-valve 81, an engine ECU or load feedback circuit to command and actuate the phase-gear 188 of the sub-crankshaft, thereby adjusting the active-cooling-phase in the range of 45 degree to 150 degree; the phase gear 188 can be actuated with hydraulic mechanisms or mechanical mechanisms controlled by said engine ECU or said load feedback circuit.

The active-threshold-control system is more preferably to include a peak pressure sensor in the cooling-cylinder 30 to detect the maximum pressure during the first-cold-compression-process and the second-cold-compression-process, and the engine ECU will be fed with this maximum pressure information to compute if the compressed-air in the cooling-cylinder 30 is over-pressurized; if the maximum pressure in the cooling-cylinder 30 cannot drop to an acceptable range, said engine ECU will gradually increase the value of the active-cooling-phase until an acceptable compression pressure is achieved.

Generally, the active-cooling-phase should be shifted in the range of 90 degree to 150 degree for the engine operation in the heavy load condition; whereas the active-cooling-phase should be shifted in the range between 60 degree and 120 degree in the medium load condition and the light load condition.

For the active-threshold-control type self-cooling engine utilizing the EGR or the lean-burn technology, wherein the combustion pressure in the primary-power-cylinder and the secondary-power-cylinder may drop at a relatively fast rate after the ignition, the active-cooling-phase can be shifted in the range between 45 degree and 75 degree in the extremely light load condition.

The primary-coordinate-channel 60 is an air-passage connecting between the top section of the cooling-cylinder 30 and the primary-power-cylinder 10; the end of the primary-coordinate-channel 60 on the side of the cooling-cylinder 30 is the first-input-port, the end of the primary-coordinate-channel 60 on the side of the primary-power-cylinder 10 is the first-output-port.

The secondary-coordinate-channel 80 is an air-passage connecting between the top section of the cooling-cylinder 30 and the secondary-coordinate-channel 80; the end of the secondary-coordinate-channel 80 on the side of the cooling-cylinder 30 is the second-input-port, the end of the secondary-coordinate-channel 80 on the side of the secondary-power-cylinder 20 is the second-output-port.

The first-input-valve 61 is open and the second-input-valve 81 is shut during the first-cooling-stroke, therefore the air of the cooling-cylinder 30 will be pushed into the primary-coordinate-channel 60 in the first-cold-compression-process and the first-injection-process through the first-input-port.

The second-input-valve 81 is open and the first-input-valve 61 is shut during the second-cooling-stroke, therefore, the air of the cooling-cylinder 30 will be pushed into the secondary-coordinate-channel 80 in the second-cold-compression-process and the second-injection-process through the second-input-port.

The first-output-port is controlled by a primary-coordinate-valve 65; the primary-coordinate-valve 65 will remain shut during the first-cold-compression-process; once the primary-coordinate-valve 65 opens to initiate the first-injection-process, the compressed-air of the primary-coordinate-channel 60 will be injected into the primary-power-cylinder 10 through the first-output-port.

The second-output-port is controlled by a secondary-coordinate-valve 85; the secondary-coordinate-valve 85 will remain shut during the second-cold-compression-process; once the secondary-coordinate-valve 85 opens to initiate the second-injection-process, the compressed-air of the secondary-coordinate-channel 80 will be injected into the secondary-power-cylinder 20 through the second-output-port.

The fuel supplying means and the ignition means are equipped in the primary-power-cylinder 10 and the secondary-power-cylinder 20, and the fuel-supplying means can be a high-pressure fuel injector or direct injection or converter (generally for LPG) or carburetor or fuel-pump or any other commonly known fuel-supplying means; the ignition means can be a spark plug or direct-injection-spark-ignition or diesel-injector depending on the fuel type.

The cooling-phase is the difference in the phase difference between the primary-piston/secondary-piston and the cooling-piston for the self-cooling engine; in the present invention, the cooling-phase will be actively adjusted from 45 degree to 150 degree with the phase-gear 188 during the engine operation, therefore, it is referred as the active-cooling-phase.

In the conventional 12-stroke-sequence as defined in the original dual six-stroke self-cooling internal combustion engine, the cooling-phase is fixed and the threshold angles will solely be decided by the air-fuel ratio of each power-cylinder and the air-density in the cooling-cylinder, and the maximum operational rpm is limited due to the high air-pressure prior to each injection-process in the heavy load condition (valve overheating or lubrication failure may occur); while the active-threshold-control system of the present invention can resolve this limitation and raise the engine efficiency in the heavy load condition.

The dual-phase-difference will refer to the difference in the piston position between the primary-piston 11 and the secondary-piston 21; the dual-phase-difference can range from 315 degree to 405 degree within the operational range of the 12-stroke-sequence and the self-cooling-16-process.

The 12-stroke-sequence and the self-cooling-16-process of the self-cooling engine are defined with the terms below:

The four strokes associated with the primary-piston 11 are the primary-intake-stroke, the primary-compression-stroke, the primary-power-stroke, the primary-exhaust-stroke; said associated four strokes of the primary-power-cylinder 10 will repeat every 720 degree of crankshaft rotation; said primary-intake-stroke is the down-stroke of the primary-piston 11 that will supply the air or the air-fuel mixture (depending on ignition methods into the primary-power-cylinder 10, said primary-compression-stroke is the up-stroke of the primary-piston 11 that will compress the air or the air-fuel mixture in the primary-power-cylinder 10, said primary-power-stroke is the down-stroke of the primary-piston 11 that will generate power to the main-crankshaft 190; said primary-exhaust-stroke is the up-stroke of the primary-piston 11 that will expel the cold-expansion-medium out of the primary-power-cylinder 10.

The four strokes associated with the secondary-piston 21 are the secondary-intake-stroke, the secondary-compression-stroke, the secondary-power-stroke, the secondary-exhaust-stroke; said associated four strokes of the secondary-power-cylinder 20 will repeat every 720 degree of crankshaft rotation; said secondary-intake-stroke is the down-stroke of the secondary-piston 21 that will supply the air or the air-fuel mixture (depending on the ignition methods) into the secondary-power-cylinder, said secondary-compression-stroke is the up-stroke of the secondary-piston 21 that will compress the air or the air-fuel mixture in the secondary-power-cylinder 20, said secondary-power-stroke is the down-stroke of the secondary-piston 21 that will generate power to the main-crankshaft 190; said secondary-exhaust-stroke is the up-stroke of the secondary-piston 21 that will expel the cold-expansion-medium out of the secondary-power-cylinder 20.

The four strokes associated with the cooling-piston 31 are the first-recharge-stroke, the first-cooling-stroke, the second-recharge-stroke, the second-cooling-stroke; said four strokes of the cooling-cylinder 30 will repeat every 720 degree of crankshaft rotation; said first-recharge-stroke is the down-stroke of the cooling-piston 31 that will charge air into the cooling cylinder 30, said first-cooling-stroke is the up-stroke of the cooling-piston 31 that will push the air into the primary-coordinate-channel 60, said second-recharge-stroke is another down-stroke of the cooling-piston 31 that will charge air into the cooling-cylinder 30, said second-cooling-stroke is the up-stroke of the cooling-piston 31 that will push the air into the secondary-coordinate-channel 80.

The first 8 processes of the self-cooling-16-process are performed with the primary-power-cylinder 10 and the cooling-cylinder 30.

The 1st process is the primary-intake-process, which is the process that the air-intake means (12) supplies the air into the primary-power-cylinder 10.

The 2nd process is the first-recharge-process, which is the process that the air-intake means (32) supplies the air into the cooling-cylinder 30.

The 3rd process is the primary-compression-process, which is the process that the primary-piston 11 compresses the air or the air-fuel mixture in the primary-power-cylinder 10.

The 4th process is the first-cold-compression-process which is the process that the cooling-piston 31 compresses the air into the primary-coordinate-channel 60 through the first-input-port; during this process, the first-input-valve 61 is open and the second-input-valve 81 is shut.

The 5th process is the primary-hot-expansion process, which is the process that the air-fuel mixture is combusting in the primary-power-cylinder 10 and the primary-coordinate-valve 65 is still shut to raise air-pressure in the primary-coordinate-channel 60.

The 6th process is the first-injection-process, which is the process that the primary-coordinate-valve 65 is opened by the force of the compressed-air, and the compressed air of the cooling-cylinder 30 and the primary-coordinate-channel 60 will be injected into the primary-power-cylinder 10 as the cooling-piston 31 continues to move toward its TDC; the hot-combusting-medium of the primary-power-cylinder 10 will be mixed with said compressed-air to form a cold-expansion-medium; the initiation timing and the termination timing of this first-injection process are actively depending on the threshold angle resulted from the active-cooling-phase and the real-time changes in the combusting pressure of the primary-power-cylinder 10.

The 7th process is the primary-cold-expansion-process, which is the process that the cold-expansion-medium continues to expand inside the primary-power-cylinder 10 after the primary-coordinate-valve 65 has shut the first-output-port.

The 8th process is the primary-exhaust-process, which is the process that the primary-power-cylinder 10 expels the cold-expansion-medium with its associated exhaust means (18).

The next 8 processes of the self-cooling-16-process are performed with the secondary-power-cylinder 20 and the cooling-cylinder 30.

The 9th process is the secondary-intake-process, which is the process that the air-intake means (22) supplies the air into the secondary-power-cylinder 20.

The 10th process is the second-recharge-process, which is the process that the air-intake means (32) supplies the air into the cooling-cylinder 30.

The 11th process is the secondary-compression-process, which is the process that the secondary-piston 21 compresses the air or the air-fuel mixture in the secondary-power-cylinder 20.

The 12th process is the second-cold-compression-process which is the process that the cooling-piston 31 compresses the air into the secondary-coordinate-channel 80 through the second-input-port; during this process, the first-input-valve 61 is shut and the second-input-valve 81 is open.

The 13th process is the secondary-hot-expansion-process, which is the process that the air-fuel mixture is combusting in the secondary-power-cylinder 20 and the secondary-coordinate-valve 85 is still shut to raise air-pressure in the secondary-coordinate-channel 80.

The 14th process is the second-injection-process, which is the process that the secondary-coordinate-valve 85 is opened by the force of the compressed-air, and the compressed-air of the cooling-cylinder 30 and the secondary-coordinate-channel 80 will be injected into the secondary-power-cylinder 20 as the cooling-piston 31 continues to move toward its TDC; the hot-combusting-medium of the secondary-power-cylinder 20 will be mixed with said compressed-air to form a cold-expansion-medium; the initiation timing and the termination timing of this second-injection process are actively depending on the threshold angle resulted from the active-cooling-phase and the real-time changes in the combusting pressure of the secondary-power-cylinder 20.

The 15th process is called the secondary-cold-expansion-process, which is the process that the cold-expansion-medium continues to expand inside the secondary-power-cylinder 20 after the secondary-coordinate-valve 85 has shut the second-output-port.

The 16th process is called the secondary-exhaust-process, which is the process that the secondary-power-cylinder 20 expels the cold-expansion-medium with its associated exhaust means (28).

To further elaborate the active-threshold-control system and the active-cooling-phase, it is necessary to define the threshold angles for each injection process in the self-cooling-16-process; the threshold angles of the first-injection-process and the second-injection-process are defined as below:

The threshold angle of the first-injection-process is the crankshaft reference angle, at which the air-pressure of primary-coordinate-channel 60 increases to higher than the combusting pressure of the primary-power-cylinder 10, the first-injection-process must be initiated after this threshold angle so that the hot-combusting-medium of the primary-power-cylinder 10 will not charge into the primary-coordinate-channel 60 at the initiation of the first-injection-process; generally, the threshold angle of the first-injection-process can range from the last 90 degree to the last 10 degree of the first-cooling-stroke, in other words the earliest possible initiation timing of the first-injection-process is at 90 degree before the TDC of the cooling-piston 31 during the first-cooling-stroke, whereas the latest possible initiation timing of the first-injection-process is at 10 degree before the TDC of the cooling-piston 31 during the first-cooling-stroke.

The threshold angle of the second-injection-process is the crankshaft reference angle, at which the air-pressure of the secondary-coordinate-channel 80 increases to higher than the combusting pressure of the secondary-power-cylinder 20; the second-injection-process must be initiated after this threshold angle so that the hot-combusting-medium of the secondary-power-cylinder 20 will not charge into the secondary-coordinate-channel 80 at the initiation of the second-injection-process; generally, the threshold angle of the second-injection-process can range from the last 90 degree to the last 10 degree of the second-cooling-stroke, in other words the earliest possible initiation timing of the second-injection-process is at 90 degree before the TDC of the cooling-piston 31 during the second-cooling-stroke, whereas the latest possible initiation timing of the second-injection-process is at 10 degree before the TDC of the cooling-piston 31 during the second-cooling-stroke.

A more detailed description of the cylinder condition prior to the first-injection-process is provided below for understanding the concept of the threshold angle.

Prior to the initiation of the first-injection-process, the cooling-piston 31 will compress the air of the cooling-cylinder 30 into the primary-coordinate-channel 60 through the first-input-port, the air-pressure of the primary-coordinate-channel 60 will be increased as the cooling-piston 31 continues to move toward its TDC, meanwhile the pressure of the primary-power-cylinder 10 will decrease as the primary-piston 11 moves toward its BDC; at a point between the last 90 degree and the last 10 degree of the first-cooling-stroke, the air-pressure of the primary-coordinate-channel 60 will increase to higher than the pressure of the primary-power-cylinder 10, and the crankshaft reference angle at this time is defined as the threshold angle of the first-injection-process.

The conventional self-cooling engine cannot efficiently limit the compression pressure of the cooling-cylinder in the high power output condition; for a more figurative example with a conventional self-cooling engine constructed of a fixed cooling-phase of 60 degree, when this engine is operating with high power output, the combusting pressure of each power-cylinder may be as high as 400 psi at the threshold angle (assuming this threshold angle is at about 400 degree of crankshaft reference angle and the cooling-cylinder will be compressed to about 1/50 of its maximum volume to reach an air-pressure of 400 psi), even though the air-pressure of the cooling-cylinder can still inject the compressed-air to the primary-power-cylinder, the energy efficiency of the self-cooling engine will drop significantly due to high energy loss during the air compression in the cooling-cylinder, and opening each coordinate-valve at a high temperature (the combusting temperature at this threshold angle could be as high as 2000 degree Celsius) will easily damage each coordinate-valve in the long term, furthermore, the cooling effect and the power output of each cold-expansion-process will be greatly reduced, which result in a higher expansion temperature but lower expansion pressure; therefore, the active-threshold-control system of the present invention is developed to solve the above-mentioned drawbacks of the conventional self-cooling engine.

The active-threshold-control system will limit the air-pressure of the cooling-cylinder by delaying the threshold angles and the initiation timing of each injection-process in the high power output condition; as the self-cooling engine increases its power output with higher air-fuel ratio, each power-cylinder will have a higher combusting pressure during its associated hot-expansion-process, therefore, the active-threshold-control system will increase the value of the active-cooling-phase to compensate with the changes in the combusting pressure, so that the cooling-piston will reach its TDC position at a later crankshaft reference angle, thereby shifting the initiation timings of the first-injection-process and the second-injection-process.

For a more figurative example, when an active-threshold-control type self-cooling engine of the present invention is operating in the medium load condition as in Sequence Table.1M, the active-cooling-phase is set to 75 degree, assuming that the combusting pressure of primary-power-cylinder will drop to 180 psi at 405 degree of crankshaft reference angle while the air of the cooling-cylinder can be compressed to 180 psi at 405 degree of crankshaft reference angle, so that the threshold angle and the initiation timing of the first-injection-process in this condition is set at 405 degree.

As the power output increases with higher air-fuel ratio, the combusting process of the primary-power-cylinder can sustain at high pressure for a longer time, so the combusting pressure is still much higher than the air-pressure of the primary-coordinate-channel at 405 degree of crankshaft reference angle, in order to compensate this change in the combusting pressure, the active-threshold-control system increases the active-cooling-phase to 120 degree as in Sequence Table.1H to setback the initiation of each injection-process, in this case, now assuming that the combusting pressure of the primary-power-cylinder is dropped to about 200 psi at 435 degree, and the air of the cooling-cylinder is compressed to 200 psi at 435 degree, so this threshold angle is shifted to 435 degree, and the maximum compression pressure of the compressed-air in each coordinate-channel is reduced to 200 psi in this condition. (the assumed pressure figures are only estimated for the ease of the comprehension, and these number figures are not elements nor limitation).

On the other hand, the active-threshold-control system will decrease the value of the active-cooling-phase as the engine load decreases; the active-cooling-phase can adjusted to as low as 45 degree (the minimum value) with the active-threshold control system in the extremely light load condition, thereby actively advancing the threshold angles and the initiation timings of each injection-process to raise the energy efficiency.

Sequence Table.1M demonstrates an example of the self-cooling-16-process in the medium load condition with the presumption that the threshold angles are at 405 degree for the first-injection-process and 765 degree for the second-injection-process when the active-cooling-phase is set to 75 degree with the phase-gear; the duration of the first-injection-process and the second-injection-process are approximately 30 degree of crankshaft rotation, the durations of the primary-hot-expansion-process and the secondary-hot-expansion-process are approximately 45 degree of crankshaft rotation in Sequence Table 1M.

Sequence Table.1L demonstrates an example of the self-cooling-16-process in the extremely light load condition with the presumption that the threshold angles are at 380 degree for the first-injection-process and 740 degree for the second-injection-process when the active-cooling-phase is set to 45 degree with the phase-gear; the duration of the each injection-process is approximately 25 degree of crankshaft rotation, the duration of each hot-expansion-process is approximately 20 degree of crankshaft rotation in Sequence Table.1L.

Sequence Table.1H demonstrates an example of the self-cooling-16-process in the heavy load condition with the presumption that the threshold angles are at 435 degree for the first-injection-process and the 795 degree for the second-injection-process when the active-cooling-phase is set to 120 degree with the phase-gear; the duration of each injection-process is approximately 45 degree of crankshaft rotation, the duration of each hot-expansion-process is approximately 75 degree of crankshaft rotation in Sequence Table 1H.

The ignition timings in Sequence Table.1L and Sequence Table.1M and Sequence Table.1H are presumed to be at the TDC position of the primary-piston or the secondary-piston for the ease of comparison, it should be noted that the ignition timings (starting point of each hot-expansion-process) will vary in the actual construction for optimizing the energy efficiency.

In short, the operation of the active-threshold-control system will detect or calculate the compression pressure with the information fed back by the pressure measuring means, and the engine ECU will instruct the phase-gear to adjust the value of the active-cooling-phase in order to regulate the peak compression pressure of the cooling cylinder during each cold-compression-process within an acceptable range for continuous high power output operation.

Since the conventional self-cooling engine is not a well-known concept in the academic field, and the present invention is a further developed configuration of the conventional self-cooling engine, a step-by-step demonstration of the self-cooling-16 processes will be provided below with the drawings of FIG. 1A to FIG. 1P to show the valve condition in each process, wherein said drawings are based on the configuration in Sequence Table.1M only, the valve conditions in other configuration will vary accordingly.

As shown in FIG. 1A is the beginning of the primary-intake-process (1st process), the primary-intake-valve 12 is open to supply air into the primary-power-cylinder 10 from the common-intake-manifold 101, wherein the primary-piston 11 is moving toward its BDC, this process duration is from 0 degree to 180 degree of crankshaft reference angle in the particular condition; FIG. 1A shows the valve condition at approximate 15 degree of crankshaft reference angle.

As shown in FIG. 1B is the beginning of the first-recharge-process (2nd process), the cooling-intake-valve 32 is open to supply air into the cooling-cylinder 30 from the cooling-intake-manifold 102, wherein the cooling-piston 31 is moving toward its BDC, this process duration is from 75 degree to 255 degree of crankshaft reference angle in the particular condition; FIG. 1B shows the valve condition at approximate 105 degree of crankshaft reference angle.

As shown in FIG. 1C is the beginning of the primary-compression-process (3rd process), the primary-intake-valve 12 is shut and the primary-piston 11 is moving toward its TDC to compress the air in the primary-power-cylinder 10, this process duration is from 180 degree to 360 degree of crankshaft reference angle in the particular condition; FIG. 1C shows the valve condition at approximate 195 degree of crankshaft reference angle.

During either the primary-intake-process or the primary-compression-process, the fuel will be supplied into the primary-power-cylinder 10 with its fuel-supplying means. The primary-power-cylinder 10 will initiate the ignition with the air and the fuel therein between 35 degree before the TDC of the primary-piston and 40 degree after the TDC of the primary-piston, the ignition timing can be assumed as 360 degree of crankshaft reference angle in this embodiment.

As shown in FIG. 1D is the beginning of the first-cold-compression-process (4th process), the first-input-valve 61 will be opened while the second-input-valve 81 will be shut, so the cooling-piston 31 will compress the air into the primary-coordinate-channel 60 through the first-input-port during the first-cold-compression-process; this process duration is from 255 degree to 405 degree of crankshaft reference angle in the particular condition with the presumption that the threshold angle of the first-injection-process is controlled at 405 degree; FIG. 1D shows the valve condition at approximate 260 degree of crankshaft reference angle.

As shown in FIG. 1E is the beginning of the primary-hot-expansion-process (5th process), the air and the fuel are ignited in the primary-power-cylinder 10 to generate power to the main-crankshaft 190; during the primary-hot-expansion-process, the primary-coordinate-channel 60 will continue to increase the air-pressure therein until the threshold angle of the first-injection-process; this process duration is from 360 degree to 405 degree of crankshaft reference angle in this particular condition with the presumption that the threshold angle of the first-injection-process is controlled at 405 degree; FIG. 1E shows the valve condition at approximate 365 degree of crankshaft reference angle.

As shown in FIG. 1F is the beginning of the first-injection-process (6th process), the primary-coordinate-valve 65 is actuated at the threshold angle and will continue to open until most of the air in the primary-coordinate-channel 60 is injected into the primary-power-cylinder 10 to form a cold-expansion-medium; at the end of this process, a small portion of the compressed-air may remain in the primary-coordinate-channel 60 when the primary-coordinate-valve 65 closes; this process duration is form 405 degree to 435 degree of crankshaft reference angle in this particular condition with the presumption that the threshold angle of the first-injection-process is controlled at 405 degree; FIG. 1F shows the valve condition at approximate 410 degree of crankshaft reference angle.

At the end of the first-injection-process, the primary-coordinate-valve 65 will start to shut after the air-pressure of the primary-coordinate-channel 60 has decreased to equal to the pressure in the primary-power-cylinder 10; the process durations of the first-injection-process can range from 5 degree to 90 degree of crankshaft rotation.

As shown in FIG. 1G is the beginning of the primary-cold-expansion-process (7th process), the primary-piston 11 continues to move toward its BDC after the cold-expansion-medium has formed in the primary-power-cylinder 10, and the cold-expansion-medium continues to expand and push the primary-piston 11, this process duration is from 435 degree to 540 degree of crankshaft reference angle in this particular condition; FIG. 1G shows the valve condition at approximate 435 degree of crankshaft reference angle.

As shown in FIG. 1H is the beginning of the primary-exhaust-process (8th process), the primary-exhaust-valve 18 is open to expel the cold-expansion-medium out of the primary-power-cylinder 10 while the primary-piston 11 moves toward its TDC; this process duration is from 540 degree to 720 degree of crankshaft reference angle in this particular condition; FIG. 1H shows the valve condition at approximate 550 degree of crankshaft reference angle.

As shown in FIG. 1I is the beginning of the secondary-intake-process (9th process), the secondary-intake-valve 22 is open to supply air into the secondary-power-cylinder 20 from the common-intake-manifold 101, wherein the secondary-piston 21 is moving toward its BDC; this process duration is from 360 degree to 540 degree of crankshaft reference angle in this particular condition; FIG. 1I shows the valve condition at approximate 370 degree of crankshaft reference angle.

As shown in FIG. 1J is the beginning of the second-recharge-process (10th process), the cooling-intake-valve 32 is open to supply air into the cooling-cylinder 30 from the cooling-intake-manifold 102, wherein the cooling-piston 31 is moving toward its BDC; this process duration is from 435 degree to 615 degree of crankshaft reference angle in this particular condition; FIG. 1J shows the valve condition at approximate 465 degree of crankshaft reference angle.

As shown in FIG. 1K is the beginning of the secondary-compression-process (11th process), the secondary-intake-valve 22 is shut and the secondary-piston 21 is moving toward its TDC to compress the air in the secondary-power-cylinder 20; this process duration is from 540 degree to 720 degree of crankshaft reference angle in this particular condition; FIG. 1K shows the valve condition at approximate 555 degree of crankshaft reference angle.

During either the secondary-intake-process or the secondary-compression-process, the fuel will be supplied into the secondary-power-cylinder 20 with its fuel-supplying means. The secondary-power-cylinder 20 will initiate ignition with the air and the fuel therein between 35 degree before the TDC of the secondary-piston and 40 degree after the TDC of the secondary-piston, the ignition timing can be assumed as 720 degree of crankshaft reference angle in this embodiment.

As shown in FIG. 1L is the beginning of the second-cold-compression-process (12th process), the second-input-valve 81 will be opened while the first-input-valve 61 will be shut, so the cooling-piston 31 will compress the air into the secondary-coordinate-channel 80 through the second-input-port during the second-cold-compression-process; this process duration is from 615 degree to 765 degree of crankshaft reference angle in this particular condition with the presumption that the threshold angle of the second-injection-process is controlled at 765 degree; FIG. 1L shows the valve condition at approximate 620 degree of crankshaft reference angle.

As shown in FIG. 1M is the beginning of the secondary-hot-expansion-process (13th process), the air and the fuel are ignited in the secondary-power-cylinder 20 to generate power to the main-crankshaft 190; during the secondary-hot-expansion-process, the secondary-coordinate-channel 80 will continue to increase the air-pressure therein the threshold angle of the second-injection-process; this duration process is from 720 degree to 765 degree of crankshaft reference angle in this particular condition with the presumption that the threshold angle of the second-injection-process is controlled at 765 degree; FIG. 1M shows the valve condition at approximate 725 degree of crankshaft reference angle.

As shown in FIG. 1N is the beginning of the second-injection-process (14th process), the secondary-coordinate-valve 85 is actuated at the threshold angle and will continue to open until most of the air in the secondary-coordinate-channel 80 is injected into the secondary-power-cylinder 20 to form a cold-expansion medium, at the end of this process, a small portion of the compressed-air may remain in the secondary-coordinate-channel 80 when the secondary-coordinate-valve 85 closes; this process duration is from 765 degree to 795 degree of crankshaft reference angle in this particular condition with the presumption that the threshold angle of the second-injection-process is controlled at 765 degree; FIG. 1N shows the valve condition at approximate 770 degree of crankshaft reference angle.

At the end of the second-injection-process, the secondary-coordinate-valve 85 will start to shut after the air-pressure of the secondary-coordinate-channel 80 has decreased to equal to the pressure in the secondary-power-cylinder 20; the process durations of the second-injection-process can range from 5 degree to 90 degree of crankshaft rotation.

As shown in FIG. 1O is the beginning of the secondary-cold-expansion-process (15th process), the secondary-piston 21 continues to move toward its BDC after the cold-expansion-medium has formed in the secondary-power-cylinder 20, and the cold-expansion-medium continues to expand and push the secondary-piston 21; this process duration is from 795 degree to 900 degree of crankshaft reference angle in this particular condition with the presumption that the threshold angle of the second-injection-process is controlled at 765 degree; FIG. 10 shows the valve condition at approximate 795 degree of crankshaft reference angle.

As shown in FIG. 1P is the beginning of the secondary-exhaust-process (16th process), the secondary-exhaust-valve 28 is open to expel the cold-expansion-medium out of the secondary-power-cylinder 20 while the secondary-piston 21 moves toward its TDC position; this process duration is from 900 degree to 1080 degree of crankshaft reference angle in this particular condition; FIG. 1P shows the valve condition at approximate 915 degree of crankshaft reference angle.

FIG. 1A to FIG. 1P are based on the operation of Sequence Table.1M; it should be noted that the settings of the active-cooling-phase (45 degree 150 degree) in different power output conditions will yield a corresponding shift in the process durations of the self-cooling-processes.

When the active-threshold-control type self-cooling engine is operating with a decreasing engine load, the threshold angles will be advanced by the active-cooling-phase, and the process durations of the self-cooling-16-process will change accordingly; Sequence Table.1L shows an example of the self-cooling-16-process when the active-cooling-phase is adjusted to its minimum value (45 degree), the compressed-air of the cooling-cylinder will be injected at an early threshold angle, and each cold-expansion-process will have a relatively longer duration in comparison to that of the configuration in the medium load condition.

When the active-threshold-control type self-cooling engine is operating in a increasing engine load, the threshold angles will be delayed by the active-cooling-phase, and the process durations of the self-cooling-16-process will change accordingly; Sequence Table.1H shows an example of the self-cooling-16-process when the active-cooling-phase is adjusted to 120 degree (the maximum value is 150 degree), the compressed-air of the cooling-cylinder will be injected at a later threshold angle, and each injection-process will have a relative longer duration, while each cold-expansion-process will have a relatively shorter duration in comparison to that of the configuration in the medium load condition.

The engine ECU can also be input with the information of the air-fuel ratio and the air-intake volume of each cylinder and the ignition timings to estimate the maximum pressure during the first-cold-compression-process and the second-cold-compression-process, thereby instructing said phase-gear to the active-cooling-phase for the optimal energy efficiency.

The peak pressure measuring means (peak-pressure sensor) can also be installed in the primary-coordinate-channel and the secondary-coordinate-channel for detecting the peak pressure in the first-cold-compression-process and the second-cold-compression-process.

The active-threshold-control type self-cooling engine can be constructed in a few different configurations, and simplest form is the configuration of the symmetrical 12-stroke-sequence, which has a dual-phase-difference of 360 degree, however, the asymmetrical 12-stroke-sequence is preferable in the applications where the vibration resonance is essential.

In the asymmetrical 12-stroke-sequence configurations, the primary-piston and the secondary-piston can have a dual-phase-difference from 315 degree to 405 degree (other than 360 degree); for example, with the dual-phase-difference of 390 degree, the primary-intake-stroke begins at 0 degree of crankshaft reference angle and the secondary-intake-stroke begins at 390 degree of crankshaft reference angle.

For larger power applications, it is also possible to construct the present invention in the triple-crankshaft configurations, wherein all the primary-pistons of the self-cooling engine are connected to a primary-crankshaft, all the secondary-pistons of the self-cooling engine are connoted to a secondary-crankshaft, and all the cooling-pistons of the self-cooling engine are connected to a sub-crankshaft with a phase-gear.

Since the self-cooling engine is not a well-known topic in the current industrial field, it may be necessary to state the purpose of the self-cooling engine again; in most of the current internal combustion engines, the heat current conducting through the cylinder wall and the engine head is the source of their heat loss, and this heat current is proportional to the temperature difference between the cylinder and the expansion medium (combusting medium), therefore, by increasing the amount of the expansion medium with the injection process of the self-cooling-16-process and lowering the overall temperature will conserve relatively more energy in the expansion medium, since the heat current through the cylinder wall and the engine head is greatly reduced, in other words, a higher percentage of the energy released in the combustion process will remain in the expansion medium with the self-cooling-16-process, thus resulting in a cooler expansion with higher expansion pressure comparing to the conventional engine, and the required cooling-capacity will be reduced to about half of that of the conventional engine.

Many other alternative embodiments may be developed based on the principle and the structure elements set by the claims of the present invention and should still be considered within the scope of the present invention.

Seqence TABLE.1L The active-threshold-control system in the extremely light load condition (the active-cooling-phase adjusted to 45 degree)

NOTE: 1st = Primary-intake-process 2nd = First-recharge-process 3rd = Primary-compression-process 4th = First-cold-compression-process 5th = Primary-hot-expansion-process 6th = First-injection-process 7th = Primary-cold-expansion-process 8th = Primary-exhaust-process 9th = Secondary-intake-process 10th = Second-recharge-process 11th = Secondary-compression-process 12th = Second-cold-compression-process 13th = Secondary-hot-expansion-process 14th = Second-injection-process 15th = Secondary-cold-expansion-process 16th = Secondary-exhaust-process

Seqence TABLE.1M The active-threshold-control system in the medium load condition (the active-cooling-phase being adjusted to 75 degree)

NOTE: 1st = Primary-intake-process 2nd = First-recharge-process 3rd = Primary-compression-process 4th = First-cold-compression-process 5th = Primary-hot-expansion-process 6th = First-injection-process 7th = Primary-cold-expansion-process 8th = Primary-exhaust-process 9th = Secondary-intake-process 10th = Second-recharge-process 11th = Secondary-compression-process 12th = Second-cold-compression-process 13th = Secondary-hot-expansion-process 14th = Second-injection-process 15th = Secondary-cold-expansion-process 16th = Secondary-exhaust-process

Seqence TABLE.1H The active-threshold-control system in the heavy load condition (the active-cooling-phase being adjusted to 120 degree)

NOTE: 1st = Primary-intake-process 2nd = First-recharge-process 3rd = Primary-compression-process 4th = First-cold-compression-process 5th = Primary-hot-expansion-process 6th = First-injection-process 7th = Primary-cold-expansion-process 8th = Primary-exhaust-process 9th = Secondary-intake-process 10th = Second-recharge-process 11th = Secondary-compression-process 12th = Second-cold-compression-process 13th = Secondary-hot-expansion-process 14th = Second-injection-process 15th = Secondary-cold-expansion-process 16th = Secondary-exhaust-process 

1. An active-threshold-control type self-cooling engine comprising: a) a primary-power-cylinder (10) and a secondary-power-cylinder (20) and a cooling-cylinder (30) operating in the 12-stroke-sequence and the self-cooling-16-process with an active-threshold-control system; b) said primary-power-cylinder (10) contains a reciprocating primary-piston (11), said secondary-power-cylinder (20) contains a reciprocating secondary-piston (21); said primary-piston (11) and said secondary-piston (21) are connected to a main-crankshaft (190); said primary-piston (11) and said secondary-piston (21) can be constructed with a dual-phase-difference between 315 degree and 405 degree; c) said cooling-cylinder (30) contains a reciprocating cooling-piston (31), and said cooling-piston (31) is connected to a sub-crankshaft (180); d) said sub-crankshaft (180) is coupled to said main-crankshaft (190) with a phase-gear (188), and said phase-gear (188) can adjust the active-cooling-phase among said primary-power-cylinder (10) and said secondary-power-cylinder (20) and said cooling-cylinder (30) during the engine operation; e) said active-threshold-control system consists of a first-input-valve (61), a primary-coordinate-channel (60), a primary-coordinate-valve (65), a second-input-valve (81), a secondary-coordinate-channel (80), a secondary-coordinate-valve (85), peak-pressure measuring means for detecting the peak pressure in the first-cold-compression-process and the second-cold-compression-process, an engine ECU for instructing said phase-gear to adjust the active-cooling-phase according to the changes in the peak compression pressure in said cooling-cylinder; f) said primary-power-cylinder (10) includes air-intake means (12), exhaust means (18), ignition means (15), fuel supplying means; the four strokes of said 12-stroke-sequence associated with said primary-piston (11) are the primary-intake-stroke, the primary-compression-stroke, the primary-power-stroke, the primary-exhaust-stroke; said four strokes associated with said primary-piston (11) will repeat in said primary-power-cylinder (10) every 720 degree of crankshaft rotation; g) said secondary-power-cylinder (20) includes air-intake means (22), exhaust means (28), ignition means (25), fuel-supplying means; the four strokes of said 12-stroke-sequence associated with said secondary-piston (21) are the secondary-intake-stroke, the secondary-compression-stroke, the secondary-power-stroke, the secondary-exhaust-stroke; said four strokes associated with said secondary-piston (21) will repeat in said secondary-power-cylinder (20) every 720 degree of crankshaft rotation; h) said cooling-cylinder (30) includes air-intake means (32); the four strokes of said 12-stroke-sequence associated with said cooling-piston (31) are the first-recharge-stroke, the first-cooling-stroke, the second-recharge-stroke, and the second-cooling-stroke; said four strokes associated with said cooling-piston (31) will repeat in said cooling-cylinder every 720 degree of crankshaft rotation; i) the 8 processes of said self-cooling-16-process performed by said primary-power-cylinder (10) and said cooling-cylinder (30) are the primary-intake-process, the first-recharge-process, the primary-compression-process, the first-cold-compression-process, the primary-hot-expansion-process, the first-injection-process, the primary-cold-expansion-process, the primary-exhaust-process; j) the primary-intake-process is the process to supply air into said primary-power-cylinder (10); the first-recharge-process is the process to supply air into said cooling-cylinder (30); the primary-compression-process is the process to compress the air in said primary-power-cylinder (10), the first-cold-compression-process is the process to compress the air into said primary-coordinate-channel (60) with said cooling-piston (31); the primary-hot-expansion-process is the process to ignite the air-fuel mixture in said primary-power-cylinder (10); the first-injection-process is the process to inject the compressed air of said primary-coordinate-channel (60) into said primary-power-cylinder (10) to form a cold-expansion-medium; the primary-cold-expansion-process is the process to generate power with the cold-expansion-medium in said primary-power-cylinder (10), the primary-exhaust-process is the process to expel the cold-expansion-medium out of said primary-power-cylinder (10); k) the 8 processes of the self-cooling-16-process performed by said secondary-power-cylinder (20) and said cooling-cylinder (30) are the secondary-intake-process, the second-recharge-process, the secondary-compression-process, the second-cold-compression-process, the secondary-hot-expansion-process, the second-injection-process, the secondary-cold-expansion-process, the secondary-exhaust-process; l) the secondary-intake-process is the process to supply air into said secondary-power-cylinder (20); the second-recharge-process is the process to supply air into said cooling-cylinder (30); the secondary-compression-process is the process to compress the air in said secondary-power-cylinder (20), the second-cold-compression-process is the process to compress the air into said secondary-coordinate-channel (80) with said cooling-piston (31); the secondary-hot-expansion-process is the process to ignite the air-fuel mixture in said secondary-power-cylinder (20); the second-injection-process is the process to inject the compressed-air of said secondary-coordinate-channel (80) into said secondary-power-cylinder (20) to form a cold-expansion-medium; the secondary-cold-expansion-process is the process to generate power with the cold-expansion-medium in said secondary-power-cylinder (20), the secondary-exhaust-process is the process to expel the cold-expansion-medium out of said secondary-power-cylinder (20); m) the initiation timing of the first-injection-process will be setback by the active-cooling-phase when the overall combusting pressure of the primary-hot-expansion-process increases with higher power output, thereby limiting the maximum air-pressure of said primary-coordinate-channel (60) and reducing the energy loss caused by the air-compression during the first-cold-compression-process; n) the initiation timing of the second-injection-process will be setback by the active-cooling-phase when the overall combusting pressure of the secondary-hot-expansion-process increases with higher power output, thereby limiting the maximum air-pressure of said-secondary-coordinate-channel (80) and reducing the energy loss caused by the air-compression during the second-cold-compression-process; o) the initiation timing of the first-injection-process will range between the last 10 degree and the last 90 degree of the first-cooling-stroke; p) the initiation timing of said second-injection-process will range between the last 10 degree and the last 90 degree of the second-cooling-stroke; q) the active-cooling-phase can be set between 90 degree and 150 degree during the engine operation in the heavy load condition; r) the active-cooling-phase can be set between 60 degree and 120 degree during the engine operation in the light load condition and the medium load condition.
 2. An active-threshold-control type self-cooling engine as defined in claim 1, wherein said active-threshold-control system will decrease the value of the active-cooling-phase to advance the initiation timings of the first-injection-process and the second-injection-process to raise the energy efficiency as the engine load decreases; the active-cooling-phase may be adjusted between 45 degree and 75 degree in the extremely light load condition.
 3. An active-threshold-control type self-cooling engine as defined in claim 1, wherein said ignition means of said primary-power-cylinder and said secondary-power-cylinder are spark-plugs, and said fuel-supplying means of said primary-power-cylinder and said secondary-power-cylinder are high-pressure fuel injector.
 4. An active-threshold-control type self-cooling engine as defined in claim 1, wherein said fuel-supplying means of said primary-power-cylinder and said secondary-power-cylinder can be carburetors or direct-injection or fuel-pumps or converters.
 5. An active-threshold-control type self-cooling engine as defined in claim 1, wherein, the process durations of said first-injection-process and said second-injection-process may range from 5 degree to 90 degree of crankshaft rotation during the engine operation.
 6. An active-threshold-control type self-cooling engine as defined in claim 1, wherein; a) said primary-coordinate-valve will start to shut after the air-pressure of said primary-coordinate-channel has decreased to equal to the pressure in said primary-power-cylinder; b) said secondary-coordinate-valve will start to shut after the air-pressure of said secondary-coordinate-channel has decreased to equal to the pressure in said secondary-power-cylinder.
 7. An active-threshold-control type self-cooling engine comprising: a) a primary-power-cylinder and a secondary-power-cylinder and a cooling-cylinder operating in the 12-stroke-sequence and the self-cooling-16-process with an active-threshold-control system; b) said primary-power-cylinder contains a reciprocating primary-piston, said secondary-power-cylinder contains a reciprocating secondary-piston, and said primary-piston and said secondary-piston are connected to a main-crankshaft; c) said cooling-cylinder contains a reciprocating cooling-piston, and said cooling-piston is connected to a sub-crankshaft; d) said sub-crankshaft is coupled to said main-crankshaft with a phase-gear; said phase-gear can adjust the active-cooling-phase among said primary-piston and said secondary-piston and said cooling-piston; e) said primary-power-cylinder includes air-intake means, exhaust means, ignition means, fuel-supplying means; f) said secondary-power-cylinder includes air-intake means, exhaust means, ignition means, fuel-supplying means; g) said cooling-cylinder includes air-intake means; h) said 12-stroke-sequence includes the primary-intake-stroke, the primary-compression-stroke, the primary-power-stroke, the primary-exhaust-stroke, the secondary-intake-stroke, the secondary-compression-stroke, the secondary-power-stroke, the secondary-exhaust-stroke, the first-recharge-stroke, the first-cooling-stroke, the second-recharge-stroke, the second-cooling-stroke; h) the 8 processes of the self-cooling-16-process performed by said primary-power-cylinder and said cooling-cylinder are the primary-intake-process, the first-recharge-process, the primary-compression-process, the first-cold-compression-process, the primary-hot-expansion-process, the first-injection-process, the primary-cold-expansion-process, the primary-exhaust-process; i) the 8 processes of the self-cooling-16-process performed by said secondary-power-cylinder and said cooling-cylinder are the secondary-intake-process, the second-recharge-process, the secondary-compression-process, the second-cold-compression-process, the secondary-hot-expansion-process, the second-injection-process, the secondary-cold-expansion-process, the secondary-exhaust-process; j) said active-threshold-control system consists of a primary-coordinate-channel, a primary-coordinate-valve, a secondary-coordinate-channel, a secondary-coordinate-valve, an engine ECU for computing the optimal active-cooling-phase and the initiation timings of the first-injection-process and the second-injection-process, an actuation means controlled by said engine ECU for adjusting the active-cooling-phase with said phase gear; k) said cooling-piston will compress the air of said cooling-cylinder into said primary-coordinate-channel during the first-cold-compression-process and the first-injection-process; l) said cooling-piston will compress the air of said cooling-cylinder into said secondary-coordinate-channel during the second-cold-compression-process and the second-injection-process; m) the initiation timing of the first-injection-process will be setback by the active-cooling-phase to reduce the energy loss caused by the first-cold-compression-process when the power output increases; n) the initiation timing of the second-injection-process will be setback by the active-cooling-phase to reduce the energy loss caused by the second-cold-compression-process when the power output increases; o) the initiation timing of the first-injection-process can shift between the last 10 degree and the last 90 degree of the first-cooling-stroke; p) the initiation timing of said second-injection-process can range between the last 10 degree and the last 90 degree of the second-cooling-stroke.
 8. An active-threshold-control type self-cooling engine as defined in claim 7, wherein said active-threshold-control system will decrease the active-cooling-phase to advance the initiation timings of the first-injection-process and the second-injection-process to raise the energy efficiency as the engine load decreases.
 9. An active-threshold-control type self-cooling engine as defined in claim 7, wherein said engine ECU will be input with the information of the air-fuel ratio and the air-intake volume of each said cylinder to compute the threshold angles of the first-injection-process and the second-injection-process, thereby adjusting the active-cooling-phase to optimize the energy-efficiency.
 10. An active-threshold-control type self-cooling engine as defined in claim 7, wherein said phase-gear can be actuated with hydraulic mechanisms or gears to shift the active-cooling-phase from 45 degree to 150 degree.
 11. An active-threshold-control type self-cooling engine as defined in claim 7, wherein said primary-piston and said secondary-piston can be constructed with a dual-phase-difference between 315 degree and 405 degree.
 12. An active-threshold-control type self-cooling engine as defined in claim 7, wherein said ignition means can be high pressure fuel injectors or spark plugs; said primary-power-cylinder can be ignited between 35 degree before the TDC of said primary-piston and 40 degree after the TDC of said primary-piston; said secondary-power-cylinder can be ignited between 35 degree before the TDC of said secondary-piston and 40 degree after the TDC of said secondary-piston.
 13. An active-threshold-control type self-cooling engine as defined in claim 7, wherein, the active-cooling-phase will be set between 90 degree and 150 degree during the engine operation in the heavy load condition; the active-cooling-phase will be set between 60 degree and 120 degree during the engine operation in the medium load condition and the light load condition.
 14. An active-threshold-control type self-cooling engine comprising: a) a primary-power-cylinder and a secondary-power-cylinder and a cooling-cylinder operating in the 12-stroke-sequence and the self-cooling-16-process with an active-threshold-control system; b) said primary-power-cylinder contains a reciprocating primary-piston, and said primary-piston is connected to a primary-crankshaft; c) said secondary-power-cylinder contains a reciprocating secondary-piston, and said secondary-piston is connected to a secondary-crankshaft; d) said cooling-cylinder contains a reciprocating cooling-piston, and said cooling-piston is connected to a sub-crankshaft; e) said primary-crankshaft and said secondary-crankshaft are synchronized with gears or chains at the same speed to generate power to an output shaft; f) said sub-crankshaft is coupled to said primary-crankshaft or said secondary-crankshaft with a phase-gear to receive the torque required for the operation of said cooling-piston, and said phase-gear can adjust the active-cooling-phase among said primary-piston and said secondary-piston and said cooling-piston; g) said primary-power-cylinder includes air-intake means, exhaust means, ignition means, fuel supplying means; h) said secondary-power-cylinder includes air-intake means, exhaust means, ignition means, fuel-supplying means; i) said cooling-cylinder includes air-intake means and a peak-pressure sensor; j) said 12-stroke-sequence includes the primary-intake-stroke, the primary-compression-stroke, the primary-power-stroke, the primary-exhaust-stroke, the secondary-intake-stroke, the secondary-compression-stroke, the secondary-power-stroke, the secondary-exhaust-stroke, the first-recharge-stroke, the first-cooling-stroke, the second-recharge-stroke, the second-cooling-stroke; k) the 8 processes of the self-cooling-16-process performed by said primary-power-cylinder and said cooling-cylinder are the primary-intake-process, the first-recharge-process, the primary-compression-process, the first-cold-compression-process, the primary-hot-expansion-process, the first-injection-process, the primary-cold-expansion-process, the primary-exhaust-process; l) the primary-intake-process is the process to supply air into said primary-power-cylinder; the first-recharge-process is the process to supply air into said cooling-cylinder; the primary-compression-process is the process to compress the air in said primary-power-cylinder, the first-cold-compression-process is the process to compress the air into said primary-coordinate-channel; the primary-hot-expansion-process is the process to ignite the air-fuel mixture in said primary-power-cylinder; the first-injection-process is the process to inject the air of said primary-coordinate-channel into said primary-power-cylinder to form a cold-expansion-medium; the primary-cold-expansion-process is the process to generate power with the cold-expansion-medium in said primary-power-cylinder, the primary-exhaust-process is the process to expel the cold-expansion-medium out of said primary-power-cylinder; m) the 8 processes of the self-cooling-16-process performed by said secondary-power-cylinder and said cooling-cylinder are the secondary-intake-process, the second-recharge-process, the secondary-compression-process, the second-cold-compression-process, the secondary-hot-expansion-process, the second-injection-process, the secondary-cold-expansion-process, the secondary-exhaust-process; n) the secondary-intake-process is the process to supply air into said secondary-power-cylinder; the second-recharge-process is the process to supply air into said cooling-cylinder; the secondary-compression-process is the process to compress the air in said secondary-power-cylinder, the second-cold-compression-process is the process to compress the air into said secondary-coordinate-channel; the secondary-hot-expansion-process is the process to ignite the air-fuel mixture in said secondary-power-cylinder; the second-injection-process is the process to inject the air of said secondary-coordinate-channel into said secondary-power-cylinder to form a cold-expansion-medium; the secondary-cold-expansion-process is the process to generate power with the cold-expansion-medium in said secondary-power-cylinder, the secondary-exhaust-process is the process to expel the cold-expansion-medium out of said secondary-power-cylinder; o) said active-threshold-control system consists of a first-input-valve, a primary-coordinate-channel, a primary-coordinate-valve, a second-input-valve, a secondary-coordinate-channel, a secondary-coordinate-valve, an engine ECU for computing the optimal active-cooling-phase, and said phase-gear can set the active-cooling-phase between 45 degree and 150 degree according to the commands of said engine ECU; said active-threshold-control system will detect or calculate the peak compression pressure in the first-cold-compression-process and the second-cold-compression-process with said peak-pressure sensor, and said engine ECU will instruct the phase-gear to adjust the value of the active-cooling-phase in order to regulate the peak compression pressure of the cooling cylinder during each cold-compression-process within an acceptable range for continuous high power output operation; p) the initiation timing of the first-injection-process will be setback by the active-cooling-phase to reduce the energy loss caused by the first-cold-compression-process when the power output increases; q) the initiation timing of the second-injection-process will be setback by the active-cooling-phase to reduce the energy loss caused by the second-cold-compression-process when the power output increases; r) the initiation timing of the first-injection-process can shift between the last 10 degree and the last 90 degree of the first-cooling-stroke; s) the initiation timing of said second-injection-process can range between the last 10 degree and the last 90 degree of the second-cooling-stroke.
 15. An active-threshold-control type self-cooling engine as defined in claim 14, wherein said active-threshold-control system will decrease the active-cooling-phase to advance the initiation timings of the first-injection-process and the second-injection-process to raise the energy efficiency when the engine load decreases.
 16. An active-threshold-control type self-cooling engine as defined in claim 14 can further comprise addition pressure sensors in the primary-coordinate-channel and the secondary-coordinate-channel to provide more accurate peak pressure information to said engine ECU.
 17. An active-threshold-control type self-cooling engine as defined in claim 14, wherein said primary-piston and said secondary-piston can be constructed with a dual-phase-difference between 315 degree and 405 degree.
 18. An active-threshold-control type self-cooling engine as defined in claim 14, wherein said ignition means can be high pressure fuel injectors or spark plugs; said primary-power-cylinder can be ignited between 35 degree before the TDC of said primary-piston and 40 degree after the TDC of said primary-piston; said secondary-power-cylinder can be ignited between 35 degree before the TDC of said secondary-piston and 40 degree after the TDC of said secondary-piston.
 19. An active-threshold-control type self-cooling engine as defined in claim 14, wherein said fuel-supplying means of said primary-power-cylinder and said secondary-power-cylinder can be carburetors or direct-injection or fuel-pumps or converters.
 20. An active-threshold-control type self-cooling engine as defined in claim 14, wherein, the process durations of said first-injection-process and said second-injection-process may change from 5 degree to 90 degree of crankshaft rotation during the engine operation. 